Grid resistance.



u. L. LlNDQUISL GRID RESISTANCE.

APPLICATION FILED 1mm, 191;.

' Patented Dec. 7, 1915.

INVENTOR A TT RNEY BY M UNITED STATES PATENT OFFIQE.

DAVID L. LINDQUIST, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF JERSEY CITY,

NEW JERSEY, A CORPORATION OF NEW JERSEY.

GRID RESISTANCE.

Specification of Letters Patent.

Patented Dec. 7, 1915.

Application filed January 21, 1913. Serial No. 743,254.

To all whom it may concern:

Be it known that I, DAVID L. LINDQUIST, a. subject of the King of Sweden, residing in Yonkers, in the county of VVestchester and State of New York, have invented a new and useful Improvement in Grid Resistances, of which fication'.

My invention relates to improvements in grid resistances, and has for its object to provide a resilient means for maintaining grid resistances in yielding electrical engagement with each other.

Another object of my invention is to provide a resilient means to allow for expansion of the grids on their supporting mem bers, and thereby eliminate the tendency of the grids to injure or break its supporting members or fastenings.

Grids of the type herein shown are used extensively, and great difficulty has been experienced by the buckling of the supporting members, and the 'stnipping of the threads on the nuts, which as heretofore has been the practice, have been screwed tightly against the grids to keep them into firm electrical engagement with each other. \Vhen carrying an electric current the grids heat up and expand, and on account of being screwed tightly together, will cause the rods to buckle or lengthen beyond their elastic limit. The buckling of the rods will cause the grids to bend and touch each other, and quite often tosuch extent as to cause the grids to break, the grids being fragile. In case the threads on the nuts become stripped, it allows the grids to separate and thereby opens'the electrical circuit formed by the grids, which is a very bad feature.

The greatest difliculty has been expe rienced in keeping the grids in firm electhe following is a speci rangement. of grid resistances with my invention applied thereto; Fig. :2, is a sectional view of Fig. l.

The grids, 1, are of a Zig-zag shape, and have lugs, 2, formed thereon. The lugs are provided with slots 3, whereby the grids may be put on or taken off supporting rods at. The grids are insulated from the supporting rods by micanite tubes 5. The tubes set into clamp washers, 8, which are insulated from the grids by the insulating washers, 9. The faces on the lugs of the grids are formed to engage each other at points, whereby the grids form a continuous electrical circuit, but in order to do this.

springs, are carried on each of the rods 4, and are adjustable by the nuts 10. Nuts 10' at the other end of the rods hold the grids against the action of the springs.

The grids are divided into sections, A and B, .being so arranged to eliminate the strain on the supporting rods, which there would be if the grids were assembled in one section. Pipes, 16, are interposed between the sections, A and B of the grid resistances, and bear against clamp washers 8, and serve to separate the said resistance sections, and still to maintain the effectiveness of the springs to the sections to allow for expansion of the same, the section B being held by the nuts 10, against the action of the said springs.

Terminals, 11, may be connected at any desired point in the grid resistance, but as herein shown. the sections, A and B, are con nected in series, the circuit therethrough being as follows; from the conductor marked, the terminal. 11. section, A, of the grid resistance. terminal, 11. conductor. 12, terminal. 11. section,-B, of the grid resistance. terminal. 11", to conductor marked,

kept in yielding electrical contact with each other, and will thereby maintain the elec The rods, 4 are supported trical circuit.

by the framework 15, or any other suitable means. Y

I do not desire to limit myself to the particular construction and arrangement of parts as herein shown, but aim to cover in the appended claims allmodifications which are Within the scope of my invention.

What I claim as new and desire to secure by Letters Ifatent of the United States, is:

1. The conihination with a resistance unit comprising aplurality of sections, each section comprlsmg a plurality of grids, arranged electrically" to contact with each other, means to support the grids, a resilient means positioned thereon to maintain the grids in yielding contact with each other, and means arranged to separate the said sec- Copies otjhis patent may be obtained for DAVID L. LINDQUIST.

Witnesses:

CHARLES B. MANVI'LLE, WALTER C. STRANG.

five cents each, by addressing the Commissioner of Patents. Washington,- D. 0. 

